background: a method to track liver tumor motion signals from fluoroscopic images without any implanted gold fiducial markers was proposed in this study to overcome the adverse effects on precise tumor irradiation caused by respiratory movement. materials and methods: the method was based on the following idea: (i) before treatment, a series of fluoroscopic images corresponding to different bre...

This paper summarizes a system, called SED, "Selection of Edge DetectorsN, which is able to automatically select edge detectors and their scales to extract a given edge. The basic organization of the SED system is a collection of edge detectors within a knowledge structure about the characteristics of the given edge, the properties of the detectors and the mutual relation between them. The comb...

The edgelets produced by the Canny edge detector are first thresholded to reduce weak clutter. Beginning from an edgelet, we track along connected neighbours to get a list of edgelets. If one edgelet has more than two neighbours, we check all possible extensions of the curve, and segment the curves on a largest-first basis, breaking the others to form separate curves. This removes small spurs e...

Skeletonization is a morphological operation that transforms an original object into a subset, which is called a ‘skeleton’. Skeletonization has been intensively studied for decades and is a challenging issue especially for special target objects. This paper proposes a novel approach to the skeletonization of text images based on stroke width detection. First, the preliminary skeleton is detect...

We propose the motion direction histogram (MDH) as a new feature for abrupt shot boundary detection in video sequences. Conventional methods for abrupt shot boundary detection use a threshold difference as a measure of the feature values between consecutive images. It is difficult for such conventional methods t o detect shot boundaries in "busy" scenes, in which intensities change substantiall...

It is widely accepted that responses from onand o -center cells give rise to edges and are equivalent to edge detectors. In this paper, we point out that onand o -center cell responses provide more information than edges. We show that an edge-based representation makes the ownership of boundaries ambiguous and requires a combinatorial search to model perceptual grouping. By analyzing the di ere...

In the context of multimedia data analysis, it is often necessary to understand what happens in a scene, which can rely on detecting and tracking the different moving objects and by comparing their positions at a given time with their environment. In order to model the environment or the scene background, we consider straight lines as appropriate features. In this paper, we compare some classic...